highlight.py

#!/usr/bin/env python
"""Emulate: grep -Ff <letters> [<words>]"""
import curses
import os
import sys
import re


if hasattr(sys.stdout, 'fileno') and os.isatty(sys.stdout.fileno()):
    curses.setupterm()
    d = lambda b, encoding=sys.stdout.encoding: b.decode(encoding)
    BOLD = d(curses.tigetstr('bold'))
    RED = d(curses.tparm(curses.tigetstr("setaf"), curses.COLOR_RED))
    RESET = d(curses.tigetstr('sgr0'))
else:  # output is not to a terminal
    BOLD = RED = RESET = ''

with open(sys.argv[1]) as file:
    parts = file.read().splitlines()

# find parts, longest first
pattern = re.compile('({})'.format(
    '|'.join(map(re.escape, sorted(parts, key=len, reverse=True)))))


def highlighted(pattern, line):
    return pattern.sub(r'{BOLD}{RED}\1{RESET}'.format(**globals()), line)


# highlight found parts
for line in sys.stdin:
    if pattern.search(line):  # found pattern in the line
        sys.stdout.write(highlighted(pattern, line))